How do you assign an infinite DHCP lease?



I hope someone here might be able to help with this as the YouSee technical support were not able to.

I have a Sagecom router from YouSee, but as the wifi coverage isn’t good enough I have disabled it and now have a Deco P9 wifi mesh network that uses the YouSee as a simple modem. The problem is that the main deco unit plugged into the modem keeps losing internet connectivity.

I suspect it is due to the DHCP lease expiring and the deco not being able to automatically renew it for some reason. I am trying to stop this device from losing its lease by making it infinite. O can’t see any options on the router to let me do this though. All I can do is set the lease time up to a week for all devices (not what I want to do) or to assign reserved addresses. If I assign a reserved address, will this prevent the lease from expiring? Any help with this issue would be much appreciated as I am currently having to restart the modem about once a day and it’s very annoying.





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This is what i found about infinite DHCP lease.

What is an infinite DHCP lease?

If your network topology rarely changes and you have enough IP addresses in your address pool, you can configure DHCP to use infinite leases, that is, leases that never expire. However, infinite leases are not recommended. If you use an infinite lease, the IP address is leased to the client indefinitely.

Further More:

Should I make DHCP lease time forever?

You should not configure an infinite lease time. The reason of having DHCP is to have a central management and flexibility. Making the lease time infinite, you will kill the flexibility. You could try 2592000 which is 30 days .

You can read more about it here:https://www.google.com/search?q=How+do+you+assign+an+infinite+DHCP+lease&rlz=1CAZKSY_enDK937DK937&oq=How+do+you+assign+an+infinite+DHCP+lease&aqs=chrome..69i57j69i60&sourceid=chrome&ie=UTF-8


Thanks for the response! I'm not sure this applies to the setup I have. When you have parts of your network that never change (I.e hardwired extenders, routers etc) and you reserve specific addresses for those devices, then I think that leasing indefinitely for those devices is totally reasonable provided you can do it on a per device basis. The issue is if you setup infinite leases for everything. When devices join and leave the network then the IP address is not releases and so you will run out of addresses until you reset them all manually.

I was trying to find out if it is possible to set an infinite lease for a specific device (not all of them) so it is always tied to that device and never given up. I am not sure if setting a reserved address on this particular router for that device will do this or not?

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Im not sure that it applies either, it was to give You some pointers i the right direction. There are other users om the forum that knows more about it  im sure, when will they be Online, i dont know.

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Which Sagemcom router are you using?  (YouSee have several)


You say Sagemcom as modem, but have you tried "bridge mode"? (first Mesh unit act as router) 


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Hi James,

In DHCP when you have part of your network that does not change, and you have to use DHCP for that part, you use DHCP reservation, NOT Infinite Lease. (That is what all Professionels do.) You could  drop DHCP on that part of the network that does not change, and then just define the IP-addresses locally on the client connected (Normaly called an Static adrdress on the Client). That is the normal thing to do. I have never used Infinitte Lease time, Not even in Huge networks with multiple VLANS, Many Servers, Printers, etc. And multiple hundred users, they all use reservation, and/or Static addresses. 



It sounds like the problem is on the WAN side of router. In that case, it is not possible to alter what the DHCP server is handing out.